The present invention generally refers to open-air works, such as road overpasses, underpasses, bridges, artificial tunnels, garages, underground parkings or similar, which are erected on a substantially level area, possibly obtained by the execution of a digging before making the work.
More specifically, the invention refers to open-air works made in a modular manner, that is using a series of segments which have a general portal shape and are installed in succession along an axis of the work, until the desired dimensions of the work are reached.
In particular, the invention relates to a process for the construction of a segment of an open air work by prefabricated structural members of reinforced concrete.
A process of the type defined above is known from EP-A-219 501 and EP-A-861 358. Both these documents refer to the manufacturing of open-air works by virtue of the use of prefabricated modular structural members of the articulated type. These structural members have the advantage of being able to be produced and transported to the place of use in the extended configuration, since their dimensions in this condition do not exceed the limit shape allowed for the road transport. When they are installed, they are raised so as to fold the reinforcing rods projecting between adjacent bodies of each member, until each member reaches its final configuration.
If the span of the work is not wider than approximately 5 m, prefabricated structural members comprising five bodies separated by four articulations can be used. These members are intended to assume, in their installed condition, a portal or overturned-U shape which defines two parallel support uprights and the vault of the work, and allows to realize closed-frame box structures. The use of these structural members requires, after the installation of the prefabricated members, the manufacturing of a base concrete bed or mat in order to incorporate the support feet of the several prefabricated members and the reinforcing rods extending from the end bodies of such members.
If the span of the work is between 5 and 15 m approximately, prefabricated structural members having the shape of a bevelled overturned-L, in the installed condition, are used, which are placed side by side in pairs so that each pair of members constitutes a segment having a portal shape. Each of these prefabricated members comprises three bodies separated by two articulations and rests in an articulated manner through a so-called “static hinge” on a respective continuous foundation plinth. A further “static hinge” is made between the two members which constitute each segment of the work, in such a manner that each segment has a general structure of the triple-hinge arch type, one of which is in the center and two of which are at the base.